The newly seated chairman of the U.S. Federal Communications Commission has told mobile operators to voluntarily ease up on cellphone unlocking or risk being forced to do so.

FCC Chairman Tom Wheeler sent a letter on Thursday to Steve Largent, president and CEO of the mobile industry group CTIA, that called on the group to agree to several reforms around cellphone unlocking. The letter follows eight months of talks between the FCC and CTIA over a proposed amendment to the CTIA's Consumer Code, Wheeler wrote.

The FCC wants carriers to make it easier for mobile subscribers to get their phones unlocked once they've fulfilled their carrier contracts. Unlocking can allow a user to switch carriers without buying a new phone and committing to another long-term contract.

The only sticking point in the talks is over whether carriers should tell their subscribers when their devices are eligible for unlocking, Wheeler wrote.

"Absent the consumer's right to be informed about unlocking eligibility, any voluntary program would be a hollow shell," Wheeler wrote.

"Enough time has passed, and it is now time for the industry to act voluntarily or for the FCC to regulate," the letter said. "Let's set a goal of including the full unlocking rights policy in the CTIA Consumer Code before the December holiday season."

Other points in the proposed guidelines would include carriers providing a clear and readily accessible unlocking policy, unlocking devices for current and former customers when they are eligible, processing requests for unlocking within two business days, and unlocking devices for military personnel when they are deployed.

In March, the White House affirmed a call for cellphone unlocking rights that came in a petition to its "We The People" online forum. The petition, signed by 114,000 people, asked the government to legalize unlocking.